Artificial tooth



Sept. 10, 1940.

s. MYERSQN ARTIFICIAL TOOTH Filed Sept. 7, 1935 2 Sheets-Sheet l iiwwfi/ zyefisoaa S. MYERSON ARTIFICIAL TOOTH Sept. 10, 1940.

Filed Sept. 7, 1935 2 Sheets-Sheet 2 .ZLQELUeJtZO 7'. iflwrajgyerso 71/ Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE '1 Claims.

The present invention relates to artificial teeth, particularly porcelain teeth.

In a copending application, Serial No. 39,580, filed September 7, 1935, a new and improved artificial tooth is described, together with a new and improved method of mounting teeth upon a support and involving but a single baking.

An object of the present invention is to provide an improved artificial-tooth structure of the above-described character.

Other and further objects will beexplained hereinafter and will be particularly pointed out in the appended claims.

The invention will now be explained in connection with the accompanying drawings, in which Fig. 1 is a side elevation of a primary bicuspid tooth body constructed in accordance with the present invention; Fig. 2 is a corresponding perspective, showing a supporting bar waxed in the slot thereof; Fig. 3 is a view similar to Fig. 1 of an anterior, or front, tooth, and showing the supporting bar waxed in the recess thereof; Figs. 4, 5, 6 and 7 are perspectives of supporting bars; Fig. 8 is a view similar to Fig. 3 of a primary tooth body having a modified slot; Fig. 9 is an elevation, partly in section, illustrating a step in the technique; Fig. 10 is a longitudinal section illustrating a finished bridge in position; Fig. 11 is a perspective, illustrating a step in a method of manufacturing a supporting ham-Figs. 12 and 13 are perspectives illustrating further steps thereof; Fig, 14 is a side view similar to Fig. 1 of a further modified tooth; Fig. 15 is a similar view, showing the reinforcing bar of Fig. 13 mounted in the recess thereof; Fig. 16 is a lingual elevation of two completed teeth, mounted on a supporting bar at the ends of which are lateral plates secured to abutments and inset in the dummies; Fig. 17 is a corresponding buccal elevation; Fig. 18 is a perspective corresponding to the side view of Fig. 15; Fig. 19 is a top occlusal plan of two completed teeth, mounted on a supporting bar one end of which is provided with a key joint member; Fig. 20 is a similar plan of a natural tooth having a gold or other molar inlay abutment provided with a recess for receiving the key joint member illustrated in Fig. 19; and Figs. 21 and 22 are views similar to Fig. 1 of further modifications.

As described in the said application, the completed tooth may comprise a primary porcelain tooth body, as illustrated, for example, in Figs. 1, 14, 21 and 22, having a relatively narrow slot extending transversely of the tooth, between,

say, its mesial face 2 and its distal face 4. The slot may assume any of a large number of shapes, and it may be of varying sizes. It may be formed in any desired way, as by previously baking the primary tooth body with the slot 5 therein, or by subsequent cutting of the slot in an unslotted tooth. In Figs. 1, 2, 3, 8, 9 and 10, the slot is shown as extending not only between the mesial and distal faces of the tooth, but as extending also to the occlusal face 6 of the 10 tooth, the mouth of the slot being shown at 5; in Fig. 22, the slot extends to the lingual face 8, the mouth of the slot being shown at I; in Figs. 14, 15 and 18, the slot is shown extending to the gingival face 20, the mouth of the slot 15 being shown at 9; and in Fig. 21, the slot does not open upon any of the .teeth faces except the said mesial and distal faces, being otherwise disposed interiorly of the tooth body. The oppositely disposed walls of the slot are spaced :0 from each other by a distance that is small compared to the corresponding width of the tooth. In Figs. 1, 2, 3, 8, 14, 15 and 18, for example, the distance between the walls I 0 and I2 or II and I 3 of the slot is small compared to the distance between the lingual face 8 and the buccal face I4; and in Fig. 22, the distance between the walls I6 and I8 is small compared to g the distance between the occlusal face 6 and the gingival face 20.

The slot is intended to receive a supporting bar. This bar may have any desired shape, and several shapes are illustrated in the said application. It may, for example, have the T shape illustrated in Figs. 2, 3, 4, 9 to 13, 15, 18 and 19, 15 the Y shape illustrated in Fig. 5, the cross shape illustrated in Fig. 6, or the V shape illustrated in Fig. 7. These differently shaped bars are resistant to different forces in different directions. Whatever the shape of the supporting 0 bar, its ends may be fixed to abutments l1 and H3, or copings 2| and 23, or keys 25 or other natural-tooth supports, in any desired way, as by soldering. If abutments l1 and 19 are employed, they may be temporarily mounted upon 8 natural teeth (not shown); if copings 2| and 23 are used, they may be temporarily mounted on the crowns of natural teeth 21 and 29, ground to the illustrated shapes, in the form of conical stumps; and if keys 25 are used, they may be temporarily slid into key ways 3| in gold or other inlays 33 of a natural tooth '35. The copings 2i and 23 are shown provided with porcelain jacket crowns 43 and 45, respectively, in order not to expose any metal. The coplngs 2| .5

and 23 are made by taking impressions of the natural, ground-down teeth 21 and 29, after which metal dies are made to represent the crowns 43 and 45, and the platinum or other metal copings 2| and 23 are made to fit the conical stumps of the natural teeth 21 and 29 in the manner usual to the art.

The primary, porcelain tooth body is then mounted upon the supporting bar, carried upon a suitably prepared model of the parts of the mouth. The dentist adjusts the primary tooth body to the proper position on the supporting bar, after which he fills up the slot with a secondary porcelain tooth body 26, integrally uniting this secondary tooth body to the walls of the slot by baking, with the supporting bar embedded in'the secondary porcelain tooth body; where a plurality of teeth are made, the secondary porcelain tooth body also unites them at their contacts or near contacts with each other. The conjunctions are preferably as great in area as aesthetics will permit. An integral bridge structure is thus provided that, though constituted of three parts, namely, the primary porcelain body or bodies, the secondary porcelain tooth body, and the supporting bar,is as rigid and firm as a onepiece tooth structure. The shape and the size of the tooth are, however, predetermined by the shape and the size of the primary, porcelain tooth body; so that all that the dentist needs to do, if he has properly preparedhis primary tooth body, as by proper selection and grinding, to fit the space between the abutments and to meet prop erly the opposing teeth and to fit the gum ridge, is properly to adjust the primary tooth body upon the supporting bar before uniting the parts together. sary to bend the supporting bar to proper shape.

If these precautions are observed, haphazardness and guess work will be entirely eliminated, and it will be possible to provide a dental bridge having porcelain teeth of just the right size and shape, and properly positioned in the mouth.

Prior to securing the abutments l1 and I9, or the copings 2| and 23 or the keys 25 to the supporting bar, the latter may be inserted into the slots of the primary porcelain tooth bodies; though such mounting may be effected at a later time if the parts are properly designed to effect this purpose, as is explained in the said application. The supporting bar may have as many primary tooth bodies strung thereon as may be desirable; in Figs. 9, 10, 16 and 1'7, for example, two such tooth bodies are shown. The tooth body or bodies are manually adjusted upon the supporting bar until they occupy the proper position with relation to the other teeth, the tooth bodies buttingfirmly against the gingival ridge. of a model of the mouth, and properly alined,

particularly on their buccal faces and to the proper height, so as to contact the opposing'teeth;

after which the dentist inserts a temporary holding material 28 in the slot. This temporary holding material which may, for example, be melted wax, is inserted through the occlusal open mouth of the slot 5 or the lingual mouth 1, or in any other desired way, as described in the said application. By means of this wax, which may be poured into the slot, the primary tooth bodies will be held in their manually adjusted position firmly upon the supporting bar. The supporting bar, with the primary tooth body or bodies thus temporarily waxed thereto, is then removed from the model and, after the wax is trimmed to approximately the desired outlines of the baked-on The dentist may also find it to be necesporcelain or secondary porcelain, mounted in a plaster of Paris mold or retainer 31, as illustrated in Fig. 9. The plaster of Paris embeds the gingival portions of the teeth and the lower portions of the ends of the supporting bar. The abutments l1 and IS, the copings H and 23, or the keys 25 are not yet, at this time, permanently secured to the ends of the supporting bar.

After the waxed structure is embedded firmly in this retaining plaster of Paris mold 31, hot water is applied to melt out the wax. The plaster of Paris mold continues to hold the supporting bar and the primary tooth body or bodies in proper relative position after the wax has thus been melted out. The slot or slots of the primary tooth body or bodies are then filled with a raw porcelain slip, consisting of a soft, easily flowing,

This. slip is packed with a fine, wet brush, in the slot or slots, accompanied by tapping in order that the porcelain slip may flow freely and com pletely around the supporting bar, so as to embed the latter therein, and completely fill the slot. The plaster of Paris serves also to extract much of the water of the slip, thus leaving the slot or slots filled with quite a consistent, porcelain mass; but the slip may be dried also in other ways.

The next step is to bake the structure, which is removed for this purpose from the plaster of Paris retainer 31, and placed carefully on a silex tray, which is then carefully brought into a fur nace. In order to withstand the baking heat, the supporting bar may be made of platinum or a platinum-iridium alloy. As the porcelain slip becomes baked, it becomes integrally united to the walls of the slot of the primary tooth body, with the supporting member embedded therein and adhering firmly thereto. The resulting structure is almost indistinguishable from a tooth that has been originally formed in a single piece. Only a single baking is required; further bakings may involve risk of damage and distortion of the porcelain tooth body. This single baking secures the teeth not only to the bar 22, but also to each other at their contacting sides.

The advantages of having the slot of the shapes herein described and illustrated, except in Fig. 8, is that a considerable portion of the stress is withstood by the primary tooth body, and the less the porcelain slip that is disposed between the walls-of the slot, the less shrinkage there will be of the secondary porcelain tooth body in baking and the less time and skill will be required to mold it to proper shape. Also the shrinkage strains are reduced to a minimum.

The baked structure is then replaced upon the model, and the case is invested so as completely to cover the porcelain teeth and to retain the several parts in their proper positions. The ends of the supporting bar are then soldered to the copings or other abutments. The porcelain jackets may then be fitted to the copings, the jackets having lateral openings on the sides -where the .copings join the bar.

only a narrow supporting bar. This would have 76 portion 34 of the slot, between the walls I and I2, may be narrow, for the reasons before given: but the enlarged bore 32 will be considerably wider. The supporting bar may be so shaped as to have a portion both in the body portion 34 of the slot and in the bore 32. The T-shaped bar, for example, answers to this description; the stem 39 of the T is disposed in the body portion 34 of the slot and the cap 4| of the T is disposed .in the'enlar'gedbore .32. The cap 4| is wider than the width ofthe'bodyportion 34 of the slot, and extends in a direction more or less substantially parallel to the occlusal face 6 of the tooth. Because of the expense of the platinum and iridium alloys that must necessarily be employed in order to stand up under the baking, the shape and the bulk of the supporting bar are very important. The bar should have the minimum of mass necessary to withstand the resistance to strains in various directions, though suf- -ficient to support the porcelain tooth to advantage. The before-described slot, having the body portion 34 and the enlarged bore 32, furthermore, lends itself readily to mounting the T-shaped bar therein, adjusting the primary tooth body on the bar prior to pouring the wax 28, and packing the porcelain slip.

Rectangular slots, illustrated in Figs. 8 and 22, ovalslots, illustrated at 6| Fig. 21, and other shapes of slots may also be employed. The gingival slot shown in Figs. 14, 15 and 18 has a rectangular body portion for receiving the cap of the T, but it has also an upwardly extending reduced portion 61 for receiving the stem of the T, thus producing a structure having the occlusal strength of the modification shown in Figs. 1, 2 and 3, but with a gingival slot.

The T-shaped bar shown in Fig. 4 is provided with a recess 41 in the upper, free end of its stem, thus permitting a greater bulk of porcelain between the occlusal face 6 and the bottom of the recess 41, without rendering the bar liable to bending, besides involving a saving of the precious metal. The recess 41 is cut away for a distance nearly as great as, but a little less than, the distance between the mesial and distal faces of the tooth, as illustrated in Figs. 9 and 10. The stem may, however, be provided with through openings 49 into which the porcelain slip may be packed, so that strands of baked porcelain will, in the completed structure, extend through these openings to join the oppositely disposed walls l0 and I! of the slot integrally together, thus producing a'firmer bond. Something of the same effect is, therefore, produced by the recesses 41 and the openings 49. The recesses 41 and the openings 49 may, of course, be embodied in the.

other types of supporting bars, as illustrated in Figs. 5, 6 and 7.

The T bar may be made of a sheet of metal, bent into T form, as illustrated in Fig. 11, along an intermediately disposed line 55, to cause portions of the sheet on opposite sides of the line to come into contact with each other. These portions are then bent away from each other along lines 53 and 65 to pmduce a T, the portions 53 constituting the cap of the T. The cap of the T is slit, near one of the ends, along a line at right angles to the line 55, and the slit parts 53 are bent toward and against each other,

; disposed in the slot and integrally as illustrated at 51, in Fig. 12. The cut portions of the metal are then slit along the line of bend 55, between the end 59 and the line 5|, and the slit parts '51 are folded againstthe line 5|, into a plane at right angles to the line 55, as shown in Fig. 13.. The parts 51 thus constitute a lateral plate for the T-shaped bar. It is possible, of

' course, to carry out this process with other bars,

such as bars of V-shape.

Whether these lateral plates are made as illustrated, or in some other manner, each lateral plate may be received in a shallow recess 54. inset laterally in the distal or media] side of the primary tooth body, and communicating with the slot. It may be necessary to fit the plate, by

burnishing and filing, into the recess.

, When a plurality of teeth are mounted upon a common supporting bar, one of the teeth will have a recess 54 in its mesial face and another tooth in its distal face. In Figs. 16 and 17, for example, one plate is shown set into a recess 54 in the mesial face 2 of the bicuspid tooth; and another plate will be set into a corresponding recess in the distal face 4v of the molar tooth.

Further modifications may occur to persons skilled in the art, and all 'such are considered to fall within the spirit of the invention, the scope of which is defined in the appended claims.

What is claimed is:

1. An artificial tooth comprising a primary porcelain tooth bodyhaving a slot extending transversely of the tooth body between two-oppositely disposed faces thereof, the slot having oppositely disposed walls, a secondary porcelain tooth body disposed in the slot and integrally baked to the and integrally baked to the secondary tooth body,

the supporting member extending through the mesial and distal faces of the tooth andhaving a portion disposed nearer to the occlusal face of the tooth than the head of the supporting member but not extending through the said occlusal face of the tooth.

3. An artificial tooth comprising a-primary porcelain tooth body having a slot extending transversely of the tooth body between two oppositely disposed faces thereof, the slot having oppositely disposed walls, a secondary porcelain tooth body baked to the walls of the slot, and a T-shaped supporting member embedded in the secondary tooth body in the slot and integrally baked to the secondary tooth body, the stem of the T being disposed nearer to the occlusal face of the tooth than the head of the T but not extending through the said occlusal face of the tooth.

4. An artificial tooth comprising a primary porcelain tooth body having a slot extending transversely of the tooth between its mesial and distal faces, the slot having a body portion and a reduced portion, a headed supporting member the head of which is of greater width than the width of the body portion of the slot, the supporting member being disposed in the slot with its head invthebody portion and with its stem in the reduced portion of the slot, and a secondary porcelain tooth body integrally united to the walls of the slot and in which the supporting member is embedded. l

5. An artificial tooth comprising a primary porcelain tooth body having a slot extending trans: versely of the toothbetween its mesial and distal faces, the slot having a body portion and a reducedportion, the reduced portion opening upon one of thefaces between its lateral faces, a headed;supporting member the head of which isof greater width than the width of the body portion of the slot, the supporting member being disposed in the slot with its head in the body portion and with its stemin the reduced portion of the slot, and a secondary porcelain tooth body integrally united to the walls of the slot and in which the supporting member is embedded.

6. An artificial tooth constituted of porcelain and comprising a primary porcelain tooth body and a secondary porcelain tooth body integrally united together, the primary tooth body having a slot extending transversely of the tooth between its mesial and distal faces, the slot having a body portion and a reduced portion, the reduced portlon opening upon the occlusal face of the tooth between its lateral faces, the secondary porcelain tooth body being disposed in and integrally united to the walls of the slot, and a solid headed supporting member the head of which is of greater width than the width of the bodyportion of the slot, the supporting member being embedded in nearer to the occlusal face of the tooth than the head of the supportingmember but not extending through the occlusal face of the tooth.

7. An artificial tooth. constituted of porcelain andcomprising a primary porcelain tooth body and a secondary porcelain tooth body integrally united together, the primary tooth'body having a slot extending transversely of the tooth between its mesial and distal faces, the slot having a body portion and a reduced portion, the reduced portionopening upon the occlusal face of the tooth between its lateral faces, the secondary porcelain tooth body being disposed in and integrally united to the walls of the slot, and a solid supporting member in the form of a prism with T-shaped base, the head and the stem of the T being both embedded in and integrally united to the secondary tooth body and both extending from the mesial to the distal faces, with the head of the T in the body portion of the slot and with the stem of the T in the reduced portion of the slot nearer to the occlusal face of the tooth than the head of the supporting member, but not extending through the occlusal face of the tooth, the embedded stem of the T of the prism having an intermediately disposed cut-out portion.

SIMON MYERSON. 

